In the food preparation industry, the rapid cooling or heating of food is very critical. For example, when a large batch of food is prepared, for example, a stew, beans or the like, health food regulations, and safety requires the food to be cooled within a certain time period from the cooking temperature, (perhaps 140–165° F.) to the storage temperature of 40° F. The longer the food takes to cool, the longer the food will be at a temperature range conducive to the growth of harmful bacteria and the like which can spoil the food and cause illness.
The commercial food industry, for example, will often use manual labor to take large volumes of hot food and place them in plastic bags for protection and submerge the bags and food in ice baths to cool the food from the cooking temperature to the storage temperature. This is a very costly procedure given the energy and labor input that is required each time the procedure is undertaken. In addition, the bags are used to subsequently reheat the food. This process of using bags involves physically handling the food at each bag iteration. It often takes more than a four hour period to cool the food from the cooking temperature to the storage temperature. In addition to the bags and the ice baths, quite often the food is broken down into smaller pans to facilitate cooling. Again, this results in a waste of labor, energy and food and results in an increased possibility of cross-contamination. Many jurisdictions have regulations that limit the time for this cooling procedure and this must be monitored continuously.
In heating the food just before serving, time is also critical. It is desirable to keep this time as short as possible to give the preparer greater flexibility in the timing of the final meal service. Further, the shorter the interval of time to heat the food, the less time the food will be exposed to a temperature range conducive to the growth of bacteria. Also, less energy is required to heat the product to temperature and less product is lost to burning or dehydration at the edges nearest the heat source due to non-uniform heating of the product.
A need exists for a process to more rapidly heat and cool food to provide the advantages of a safer food service and to satisfy the applicable regulations, reduce energy, labor and product loss due to inefficient thermal effects.